1. Field of the Invention
This invention relates to a latch for latching together two overlapping sheets of semi-rigid material. Especially, the invention relates to a latch for articles having overlapping closure flaps, for example, cartons of all shapes and sizes, e.g. packing boxes and card wallets.
2. Acknowledgement of Prior Art
On the one hand, many cartons are formed from carton blanks having complex systems of tabs and slots to hold the cartons in erected condition and to hold any lid in closed position. Such cartons may, for example, be made from paper products such as card stock. On the other hand, wallets and other fold-over containers may be made of leather or simulated leather or plastic materials. Such containers are frequently provided with a mechanical two part latch, one part being on one flap of the container and the other part being on another flap of the container.
Other containers such as pencil cases having a fold over cover flap may have a rearwardly projecting cut-out tongue which may be biassed inwardly of the flap to slip under a catcher band on the body of the pencil case. This construction has some advantages in that material is not wasted in cutting complex tabs to project from the flap and in that the flap itself may be wholly tucked beneath the catcher band if desired. Nevertheless, it may be difficult to provide a biassing reaction in such a case to urge the tongue beneath the catcher band. Moreover, when the case is filled tightly with pencils or other contents the catcher band may become unduly tight making insertion of the tongue beneath it very difficult.
The present inventors have attempted to devise a reliable, simple, latch to hold two overlapping sheets of semi-rigid material in fixed relation one to the other.